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United States Patent |
5,683,861
|
Vishwakarma
,   et al.
|
November 4, 1997
|
Benzotriazole-based UV absorbers and photographic elements containing
them
Abstract
An ultraviolet absorbing compound of formula (I) below, and photographic
elements containing such a compound as an ultraviolet absorber:
##STR1##
wherein: R.sub.4 is a substituted alkyl group, R.sub.4 may be further
joined to either L or A* forming a ring and the benzo or phenyl ring shown
may be further substituted or unsubstituted;
L is a bivalent linking group;
p is 0 or 1;
A* is an alkyl group having an asymmetric carbon or asymmetric silicon
atom, and;
wherein the ultraviolet absorbing compound of formula (I) is a mixture of
two enantiomers about the asymmetric carbon or silicon atom of A*.
Inventors:
|
Vishwakarma; Lal C. (Rochester, NY);
Brown; Glenn M. (Rochester, NY)
|
Assignee:
|
Eastman Kodak Company (Rochester, NY)
|
Appl. No.:
|
735543 |
Filed:
|
October 23, 1996 |
Current U.S. Class: |
430/512; 430/931; 524/91; 548/260; 548/261 |
Intern'l Class: |
G03C 001/815; C08K 005/34; C07D 249/16; C07D 403/00 |
Field of Search: |
430/512,931
524/91
548/260,261
|
References Cited
U.S. Patent Documents
3272891 | Sep., 1966 | Peter et al. | 260/895.
|
3399173 | Aug., 1968 | Heller et al. | 548/260.
|
4041044 | Aug., 1977 | White | 260/308.
|
4141903 | Feb., 1979 | Adler | 260/308.
|
4224451 | Sep., 1980 | Roberts et al. | 548/260.
|
4316033 | Feb., 1982 | Ching | 524/91.
|
4719248 | Jan., 1988 | Bambury et al. | 523/108.
|
4780541 | Oct., 1988 | Seino | 548/260.
|
4835284 | May., 1989 | Seino | 548/259.
|
4943637 | Jul., 1990 | Seino et al. | 548/260.
|
5262541 | Nov., 1993 | Moshchitsky et al. | 548/260.
|
5385815 | Jan., 1995 | Schofield et al. | 430/512.
|
5500332 | Mar., 1996 | Vishwakarma et al. | 430/512.
|
Foreign Patent Documents |
0 257 151 | Mar., 1988 | EP.
| |
1324898 | Mar., 1963 | FR.
| |
1324897 | Mar., 1963 | FR.
| |
1330378 | May., 1963 | FR.
| |
960141 | Jun., 1964 | GB.
| |
981539 | Jan., 1965 | GB.
| |
991320 | May., 1965 | GB.
| |
991630 | May., 1965 | GB.
| |
991204 | May., 1965 | GB.
| |
991142 | May., 1965 | GB.
| |
90/09369 | Aug., 1990 | WO.
| |
Primary Examiner: Schillling; Richard L.
Attorney, Agent or Firm: Rice; Edith A.
Claims
We claim:
1. A photographic element comprising an ultraviolet absorbing compound of
the following structure:
##STR19##
wherein: R.sub.4 is a substituted or unsubstituted alkyl group, R.sub.4
may be further joined to either L or A* forming a ring and the benzo or
phenyl ring shown may be further substituted or unsubstituted;
L is a bivalent linking group;
p is 0 or 1;
A* is an alkyl group having an asymmetric carbon or asymmetric silicon
atom, and;
wherein the ultraviolet absorbing compound of formula (I) is a mixture of
two enantiomers about the asymmetric carbon or silicon atom of A*.
2. A photographic element according to claim 1, wherein p is 1 and L is an
alkylene group having a chain of 1 to 20 atoms in length, with or without
intervening oxygen, sulfur or nitrogen atoms; an aryl group; or a
saturated or unsaturated heterocyclic group.
3. A photographic element according to claim 2, wherein L is an alkylene
group containing at least one intervening oxygen, sulfur or nitrogen atom.
4. A photographic element according to claim 1, wherein R.sub.4, is an
alkyl group substituted with an alkoxy, halogen or cyano group.
5. A photographic element according to claim 1, wherein R.sub.4 is a
perfluoroalkyl group.
6. A photographic element according to claim 1, wherein the ultraviolet
absorbing compound is a 60/40 to 40/60 mixture of two enantiomers.
7. A photographic element according to claim 1, the element additionally
comprising at least one light sensitive silver halide emulsion layer and a
non-light sensitive layer, wherein the ultraviolet absorbing compound is
located in the non-light sensitive layer.
8. A photographic element according to claim 7, wherein the non-light
sensitive layer containing the ultraviolet absorbing compound is located
above all light sensitive layers.
9. A photographic element according to claim 1, additionally comprising a
reflective support and at least one silver halide emulsion layer, and
wherein the ultraviolet absorbing compound is located in the silver halide
emulsion layer or in a layer positioned further from the support than the
silver halide emulsion layer.
10. A photographic element according to claim 9, additionally comprising a
fluorescent brightener.
11. A photographic element according to claim 9, wherein the fluorescent
brightener absorbs ultraviolet in the 350-410 nm range in order to
fluoresce in the range of 400-500 nm.
12. A photographic element according to claim 1, wherein the ultraviolet
absorbing compound is present in an amount of between 0.2 g/m.sup.2 to 10
g/m.sup.2.
13. A photographic element according to claim 1, wherein the ultraviolet
absorbing compound is of formula (Ia):
##STR20##
wherein: R.sub.1 or R.sub.2 independently represent alkyl group, alkoxy
group, aryl group, heteroaryl group, or aryloxy group, and the alkyl or
alkoxy may contain from 1 to 5 intervening oxygen, sulfur or nitrogen
atoms, or any of R.sub.1, R.sub.2 or R.sub.3 is H, cyano or a halogen
atom, or both R.sub.1 and R.sub.2 together form an aromatic group or
hetero aromatic group, or R.sub.3 can additionally be H or 6'-hydroxy, or
5'-H or an alkyl group;
R.sub.4 an alkyl group or perfluoroalkyl group;
L is a bivalent linking group;
p is 0 or 1; and
R.sub.5, R.sub.6 and R.sub.7 are, independently: H; halogen; cyano; an
alkyl group or alkoxy group; thioalkyl group; alkylamino or arylamino
group; an aryl group or aryloxy group; or a heteroaryl group;
provided that R.sub.5, R.sub.6, and R.sub.7 are selected such that the
carbon atom to which they are attached is asymmetric;
the ultraviolet absorbing compound being a 60/40 to 40/60 mixture of two
enantiomers about the asymmetric carbon of A*.
14. A photographic element according to claim 13, wherein R.sub.5, R.sub.6
and R.sub.7 are each a 1 to 20 carbon atom alkyl group, or H.
15. A photographic element according to claim 14, wherein each of R.sub.1,
R.sub.2 and R.sub.3, is an alkyl group, alkoxy group, H or halogen.
16. A photographic element according to claim 13, wherein the ultraviolet
absorbing compound of formula (I) is a 50/50 mixture of two enantiomers.
17. A photographic element according to claim 1, the element additionally
comprising at least one light sensitive silver halide emulsion layer and a
non-light sensitive layer, wherein the ultraviolet absorbing compound is
of formula (Ib):
##STR21##
wherein: R.sub.1 or R.sub.2 independently represent alkyl group, alkoxy
group, aryl group, heteroaryl group, or aryloxy group, and the alkyl or
alkoxy may contain from 1 to 5 intervening oxygen, sulfur or nitrogen
atoms, or any of R.sub.1, R.sub.2 or R.sub.3 is H, cyano or a halogen
atom, or both R.sub.1 and R.sub.2 together form an aromatic group or
hetero aromatic group, or R.sub.3 can additionally be H or 6'-hydroxy, or
5'-H or an alkyl group;
R.sub.4 a substituted or unsubstituted alkyl group;
L is a bivalent linking group;
p is 0 or 1; and
R.sub.5, R.sub.6 and R.sub.7 are, independently: H; halogen; cyano; an
alkyl group or alkoxy group; thioalkyl group; alkylamino or arylamino
group; an aryl group or aryloxy group; or a heteroaryl group;
provided that R.sub.5, R.sub.6, and R.sub.7 are selected such that the
carbon atom to which they are attached is asymmetric;
the ultraviolet absorbing compound being a 60/40 to 40/60 mixture of two
enantiomers about the asymmetric carbon of A*.
18. A photographic element according to claim 17, wherein the ultraviolet
absorbing compound is of the formula:
##STR22##
wherein R.sub.4, R.sub.5, R.sub.6, R.sub.7, L and p are as defined in
claim 16.
19. A photographic element according to claim 18, wherein p is 1.
20. A photographic element according to claim 19, wherein L is a 1 to 10
carbon atom alkylene group.
21. A photographic element according to claim 20, wherein L is a methylene
group.
22. A photographic element according to claim 17, wherein R.sub.4 is a
perfluoro alkyl group.
23. A photographic element according to claim 17, the element additionally
comprising at least one light sensitive silver halide emulsion layer and a
non-light sensitive layer, wherein the ultraviolet absorbing compound is
located in the non-light sensitive layer.
24. A photographic element according to claim 17, wherein the non-light
sensitive layer containing the ultraviolet absorbing compound is located
above all light sensitive layers.
25. A photographic element according to claim 17, additionally comprising a
reflective support and at least one silver halide emulsion layer, and
wherein the ultraviolet absorbing compound is located in the silver halide
emulsion layer or in a layer positioned further from the support than the
silver halide emulsion layer.
Description
FIELD OF THE INVENTION
This invention relates to particular benzotriazole based W absorbing
compounds, and to photographic elements containing such compounds.
BACKGROUND
Typical photographic elements use silver halide emulsions, the silver
halide having a native sensitivity to ultraviolet radiation. Ultraviolet
radiation ("UV") as used in this application means light having a
wavelength of 300-400 nm. Such UV sensitivity is usually undesirable in
that it produces an image on the photographic element which is not visible
to the human eye. Furthermore, the image dyes in the color photographs are
known to fade due to action of UV light. Also other organic molecules such
as unused color forming couplers in the emulsion layers and optical
brighteners in the paper support degrade due to action of UV light and
generate undesirable color stains on the finished photographs. Therefore,
photographic elements typically contain a UV absorbing compound (sometimes
referred to simply as a "UV absorber"). Another function of UV absorbers
is to prevent the formation of undesirable patterns caused by
electrostatic discharge in silver halide photographic materials. In
general, IN absorbers impart light stability to organic molecules in
various products which are susceptible to degrade as a result of the
action of UV.
Generally, an effective UV absorber should have its peak absorption above a
wavelength of 320 nm. The absorption peak may be at a longer wavelength,
as long as absorption drops off sufficiently as it approaches the visual
range (approximately 400 to 700 nm) so that no visible color is shown by
the compound. In addition, to be effective, a UV absorber should have a
high extinction coefficient in the desired wavelength range. However, for
the most desirable UV protection, the high extinction coefficient should
be at those wavelengths sufficiently below the visual range so that the
compound should not be visually yellow.
UV absorbers of the benzotriazole class for photographic and other
applications are well known. They include hydroxyphenyl benzotriazoles
with various substituents on the hydroxyphenyl ring and also on the benzo
ring. 2-Hydroxyphenyl benzotriazole UV absorbers with a large class of
acylamino groups, including sec-amides, tert-amides, hydrazides,
carbamates, sulfonamides, and many others, are described in FR 1,330,378,
FR 1,324,898, FR 1,324,897, GB 991 204, GB 991 320, GB 991 142, Japanese
Kokai JP 50-121178, WO 90/09369, U.S. Pat. No. 5,500,332 and GB 991 630.
UV absorbers which are currently used in photographic products include
those of formula (II-A) and (II-B) below:
##STR2##
In the manufacture of photographic elements, UV absorbers usually are
dissolved in a high boiling organic solvent and then dispersed in an
aqueous medium containing a hydrophilic colloid, such as gelatin. Such
dispersions are typically prepared up to about two weeks prior to use. It
has been found that compounds (II-A) and (II-B) have a propensity to
crystallize out during cold storage of a dispersion containing of them and
that their intrinsic light stability is inferior.
Problem to be Solved by the Invention
It is therefore desirable to have UV absorbing compounds suitable for
photographic uses, which are relatively stable in a photographic
environment, and in particular have a low tendency to crystallize out at
ordinary temperatures at which photographic elements are manufactured,
used and/or stored, which have a higher extinction coefficient than that
of (II-A)/(II-B)(collectively referred to herein as Comparative C-1), so
that less of it needs to be used to obtain the same UV absorption, and
which have a good UV absorption spectrum offering steeper slope and
sharper drop-off at the longer wavelength side of the UV spectrum for
photographic uses.
SUMMARY OF THE INVENTION
We have now discovered that benzotriazole-based UV absorbing compounds
having tertiary-amide functional group containing an alkyl substituent
having an asymmetric carbon or silicon atom eliminate crystal forming
problem and offer superior intrinsic light stability.
One aspect of the present invention comprises an ultraviolet light
absorbing compound of formula (I):
##STR3##
wherein:
R.sub.4 is a substituted or unsubstituted alkyl group, or R.sub.4 may be
further joined to either L or A* forming a ring and the benzo or phenyl
ring shown may be further substituted or unsubstituted;
L is a bivalent linking group;
p is 0 or 1;
A* is an alkyl group having an asymmetric carbon or asymmetric silicon
atom, and
wherein the ultraviolet absorbing compound of formula (I) is a mixture of
two enantiomers about the asymmetric carbon or silicon atom of A*.
Another aspect of this invention comprises a photographic element
containing an ultra violet absorbing compound of formula (I). UV absorbing
compounds of formula (I) have a wavelength of maximum absorption
(".lambda.max") which is desirable in the longer UV region (330-380 nm),
have a sharp dropping absorption profile at wavelengths slightly shorter
than 400 nm making them useful with known fluorescent brighteners, are
relatively stable in the environment of a photographic element, do not
readily crystallize in photographic elements, and have high extinction
coefficients.
Most of the prior art W absorbers having an amide linkage with its
tertiary-nitrogen atom directly attached to phenol ring either do not have
an asymmetric carbon(s) containing alkyl substituent(s) or have an
asymmetric carbon(s) containing alkyl substituent(s) but are lacking in
tertiary nature of nitrogen atom of the amide linkage. Such compounds
include, for example:
##STR4##
The problem with such UV absorbing compounds with amide groups as disclosed
in the prior art is that these crystallize out when coated.
Advantageous Effect of the Invention
It has now been found that novel UV absorbers of the present invention have
higher molar extinction coefficient, absorption spectrum has steeper slope
and sharper drop-off on the longer wavelength side. Further, they have
extremely high solubility in high-boiling hydrophobic organic solvents
regardless of their physical state, have enhanced intrinsic light
stability, and have no tendency of crystallization in dispersions or in
photographic coatings and are therefore superior to the products of the
state of the art in the photographic field. In some cases the UV absorbers
are actually liquid and can be employed in a color photographic material
without high boiling solvents.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 shows the absorption spectra of coatings in a photographic element
for an inventive compound I-1 (dashed line) and for a mixture of
comparative compounds II-A and II-B, defined as C-1 (solid line), in total
transmission mode illustrating higher extinction and sharper drop-off for
I-1 at the longer wavelength side.
DETAILED DESCRIPTION OF THE INVENTION
In the present application, reference to ultraviolet or UV in relation to
the present invention refers to the wavelength range of 300 to 400 nm
unless the contrary is indicated. Additionally, reference to "under",
"above", "below", "upper", "lower" or the like terms in relation to layer
structure of a photographic element, is meant the relative position in
relation to light when the element is exposed in a normal manner. "Above"
or "upper" would mean closer to the light source when the element is
exposed normally, while "below" or "lower" would mean further from the
light source. Since a typical photographic element has the various layers
coated on a support, "above" or "upper" would mean further from the
support, while "below" or "under" would mean closer to the support.
Further, reference to any chemical "group" (such as alkyl group, aryl
group, heteroaryl group, and the like) includes the possibility of it
being both substituted or unsubstituted (for example, alkyl group and aryl
group include substituted and unsubstituted alkyl and substituted and
unsubstituted aryl, respectively). Generally, unless otherwise
specifically stated, substituent Groups usable on molecules herein include
any groups, whether substituted or unsubstituted, which do not destroy
properties necessary for the photographic utility. It will also be
understood throughout this application that reference to a compound of a
particular General formula includes those compounds of other more specific
formula which specific formula falls within the general formula
definition.
As is well known, enantiomers have identical structural formulas except
they are non-superimposable mirror images of one another. Further, in
reference to enantiomeric mixtures, proportions are in mole ratios. When
reference is made in this application to the ultraviolet absorbing
compound of formula (I) being a mixture of two enantiomers about the
asymmetric carbon or silicon of A*, this refers to a mixture of the two
optical isomers about the racemic carbon or silicon of A* with R and S
stereochemical configurations.
In compounds of formula (I), the bivalent linking group L may, for example,
be an alkylene group having a chain of 1 to 20 atoms, preferably 1 to 10,
more, preferably 1 to 6 and most preferably 1 to 3, in length, with or
without up to 5 (or 2 or 1) intervening oxygen, sulfur or nitrogen atoms;
an aryl group or a saturated or unsaturated heterocyclic group. However,
when L is an alkylene group, it is preferred that the carbon atoms of L
are all saturated. This means that none of the carbon atoms of L would
have any type of carbon--carbon double or triple bonds. Thus, in this
situation L would not have groups such as --C.dbd.C-- or --C.ident.C--.
The possibility of L having unsaturated atoms other than unsaturated
carbon atoms, is not excluded. For example, L could be a group such as (A)
below:
##STR5##
L may be unsubstituted or substituted with, for example, a 1 to 10 carbon
alkoxy (or 1 to 6, or 1 to 2 carbon alkoxy), a 1 to 10 carbon atom alkyl
sulfide (or 1 to 6, or 1 to 2 carbon alkyl sulfide), 0 to 10 carbon amino
(or 0 to 6, or 0 to 2 carbon amino), or halogen. By L being substituted
includes the possibility of the substituents forming a ring. For example,
L can include an alicyclic or heterocylic ring (such as a 3 to 10 or 4, 5,
or 6, membered ring). When the ring is heterocyclic it may contain, for
example, have 1, 2, or 3 heteroatoms (which may be the same or different)
selected from O, S or N. Examples of such rings as part of L include
cyclohexyl, pyrrolidinyl, tetrahydrofuranyl, tetrahydrothienyl or
piperidinyl, although less preferably such rings could also include benzo,
pyrrolo, furyl, thienyl, pyridyl or spiro-ether containing rings. L may
also include as a substituent, an ether or ester containing group.
Particularly, the ether or ester containing substituent in L may be of the
formula R.sub.8 --O--(R.sub.9).sub.n -- or R.sub.8 C(O)O--(R.sub.9).sub.n
--, where R.sub.8 and R.sub.9 are, independently, an alkyl group and n is
0 or 1. R.sub.9 may have, for example, 1 to 6 carbon atoms, while R.sub.8
may have, for example, 1 to 20 carbon atoms (for example, 1 to 10, or 6 to
10).
The benzo ring and the hydroxy substituted phenyl ring may each be further
substituted. For example, either may have 1 to 4 further substituents.
Substituents may, for example, independently be, 1 to 18 carbon alkyl (or
1 to 6, or 1 to 2 carbon alkyl), aryl (such as 6 to 20 carbon atoms),
heteroaryl (such as pyrrolo, furyl or thienyl) , aryloxy (such as 6 to 20
carbon atoms) alkoxy (such as 1 to 6 or 1 to 2 carbon alkoxy), cyano, or
halogen (for example F or Cl, particularly having Cl on the benzo ring at
the 5-and/or 6-position, and/or on the hydroxy substituted phenyl at the
5'-position). Other substituents for the benzo ring can include: a ring
fused thereto, such as a benzo, pyrrolo, furyl or thienyl rings; or
--N--CO--(L).sub.p --A* in the 5- or 6- position of the benzene ring of
the benzotriazole in which cases, the 4'-position of the hydroxyphenyl
ring can be substituted with any of the substituents described herein for
R.sub.1 or R.sub.2. Any of the alkyl and alkoxy substituents may have from
1 to 5 (or 1 to 2) intervening oxygen, sulfur or nitrogen atoms, including
or not including asymmetric centers.
R.sub.4 is an alkyl group, it may have, for example, from 1 to 20 C atoms
(or 1 to 10 or 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl or
isopropyl, or butyl or pentyl either of which may be normal, secondary or
tertiary). Substituents include alkoxy (particularly 1 to 6 carbon atoms),
halogen (particularly Cl and F), and cyano. R.sub.4 may be an electron
withdrawing alkyl group such as perfluoroalkyl group.
When R.sub.4 is not an electron withdrawing alkyl group, there may be a
hypsochromic shift (shift to a shorter wavelength) in the wavelength of
maximum UV absorption of a formula (I) compound. If desired, in such case
the wavelength of maximum UV absorption may be again shifted longer by
providing a substituent on the benzo ring of the benzotriazole, which has
an unshared electron pair. Such substituents include Cl, F, dialkylamino,
or an alkoxy. A 5'-alkyl group may also be used to correct the
hypsochromic shift.
Electron withdrawing substituents in general, are discussed in March,
Advanced Organic Chemistry, 3rd Ed., J. March, (John Wiley Sons, N.Y.;
1985) at pages 20-21, 228-229, 386-387, 494-497. In particular, preferred
electron withdrawing substituents in each case described herein, or an
electron withdrawing alkyl group for R.sub.4, would have a Hammett
.sigma..sub.p constant of greater than 0 (or greater than 0.1 or even 0.3)
and preferably between 0.1 to 1.0 (for example, between any of 0.3, 0.4,
0.5 or 0.6 to 1.0). Hammett .sigma..sub.p values are discussed in the
foregoing Advanced Organic Chemistry. Note that the "p" subscript refers
to the fact that the .sigma. values are measured with the substituents in
the para position of a benzene ring. Additional tables relating to Hammett
.sigma..sub.p constants can be found in Chemical Reviews Volume 91, pages
165-195 (authored by C. Hansch et al.).
As for A*, any alkyl group with an asymmetric carbon atom could be used.
With the appropriate substituents on the asymmetric carbon, A* may have as
little as only 1 carbon atom. The asymmetric carbon atom will preferably
have at least three different alkyl groups, which means that A* will
therefore preferably have at least 4 carbon atoms. A* may have 4 to 20 C
atoms (or preferably 6 to 20 C atoms, 4 to 10 or 4 to 6 carbon atoms). A*
is preferably of the structure --CR.sub.5 R.sub.6 R.sub.7 as shown below
in structure (Ia).
The compounds of formula (I) may particularly be of formula (Ia) below
(some of carbon atoms on the rings being numbered in formula (Ia) to
illustrate how the positions on the rings of benzotriazoles are identified
in this application):
##STR6##
or more particularly of formula (Ib):
##STR7##
More particularly, in any of formulas (I), (Ia) or (Ib), R.sub.1, R.sub.2
and R.sub.3 may be, independently, 1 to 18 (or 1 to 10, 1 to 6, or 1 to 2)
carbon alkyl or alkoxy either of which may have 1-5 (or 1 or 2)
intervening oxygen, sulfur or nitrogen atoms, or are aryl, heteroaryl, or
aryloxy. R.sub.3 may also be a 6'-hydroxy substituent. R.sub.1, R.sub.2
and R.sub.3 may also be, independently any of the foregoing substituted
with 1 to 17 (or 1 to 10, 1 to 6, or 1 or 2) carbon alkoxy, 1 to 17 (or 1
to 10, 1 to 6, or 1 or 2) carbon alkyl sulfide, 0 to 17 carbon amino (or 0
to 10, 0 to 6, or 0 to 2), or a halogen, or any of R.sub.1, R.sub.2 or
R.sub.3 may be H or a halogen (particularly chloro or fluoro) or both
R.sub.1 and R.sub.2 together form a 5 to 18 carbon atom aryl group (such
as a benzo ring) or heteroaryl ring group (for example, pyrrolo, furyl,
thienyl, pyridyl). Substituents on the foregoing rings formed by R.sub.1
and R.sub.2 may include a 1 to 17 (or 1 to 10, 1 to 6, or 1 or 2) carbon
atom alkyl or alkoxy, or a halogen.
R.sub.1, R.sub.2 and R.sub.3 may also be, ndependently: a chloro; a fluoro;
a hydroxy; a cyano; a carboxy; a carbalkoxy; a nitro; an acylamino group
(for example, an acetylamino group), carbamoyl, sulfonyl, sulfamoyl,
sulfonamido, acyloxy (for example, an acetoxy group or a benzoyloxy
group), or an oxycarbonyl group (for example, a methoxycarbonyl group,
etc.), any of which may have 1 to 18 (or 1 to 10, 1 to 6, or 1 to 2)
carbon atoms. R.sub.4 is as defined above.
Also, L may particularly have a total of 0 to 20 (or 0 to 10, or 0 to 4)
atoms and be an alkylene group of which may have 1-5 (or 1, 2 or 3)
intervening oxygen, sulfur or nitrogen atoms. Substituents on L include,
for example, a 1 to 10 (or 1 to 6, or 1 or 2) carbon alkoxy, a 1 to 10 (or
1 to 6, or 1 or 2) carbon atom alkyl sulfide, 0 to 10 (or 0 to 6, or 0 to
2) carbon amino, or with halogen.
In the above formulas, R.sub.5, R.sub.6 and R.sub.7 are, independently: H;
halogen; cyano; an alkyl group or alkoxy group; thioalkyl group;
alkylamino or arylamino group; an aryl group or aryloxy group; or a
heteroaryl group. When any of R.sub.5, R.sub.6 and R.sub.7 is an alkyl or
alkoxy group it may, for example, have from 1 to 20 C atoms (or 1 to 10 or
1 to 6, such as methyl, ethyl, propyl, butyl or pentyl). Suitable aryl
groups, aryloxy groups or heteroaryl groups may be selected from such
groups as described in connection with R.sub.1, R.sub.2 and R.sub.3 above.
Substituents on any of the foregoing groups for R.sub.5, R.sub.6 and
R.sub.7 may be selected from among the substituents on corresponding
groups for R.sub.1, R.sub.2 and R.sub.3 described above. Such substituents
include alkoxy (particularly 1 to 6 carbon atoms), halogen (particularly
Cl and F), and cyano. It is preferred that each of R.sub.5, R.sub.6 and
R.sub.7 is selected from H or alkyl groups.
It is important for the present invention that R.sub.5, R.sub.6 and R.sub.7
be different such that the carbon or silicon atom bearing those groups is
asymmetric (a racemic carbon or silicon center). However, the compound of
formula (I) could have further racemic carbon centers. When R.sub.1,
R.sub.2, R.sub.3 or R.sub.4 also contains an asymmetric carbon (or any
other substituent also contains an asymmetric carbon), such that there are
two or more asymmetric carbons in the compound, diastereomers can then be
formed. This means that the UV absorbing compound of formula (I) could
then have more than one pair of enantiomers. However, the compound should
preferably have a 60/40 to 40/60 (preferably 50/50) ratio of at least two
enantiomers (although it can have, for example a 60/40 to 40/60 ratio of
enantiomers in each of two sets of enantiomers).
Preferably, none of the carbon atoms of A* is unsaturated, except when A*
contains a carbonyl carbon atom or an aryl or heteroaryl group.
It should be noted that UV absorbing compounds are specifically
contemplated which are of formula (I) and all the specific examples below.
Examples of compounds of the present invention are shown below in Table 1
representing specific formula (Ic).
##STR8##
TABLE 1
______________________________________
R.sub.1
R.sub.2 R.sub.3
R.sub.4
L R.sub.5
R.sub.6
R.sub.7
Remark
______________________________________
H H CH.sub.3
CH.sub.3
None H CH.sub.3
C.sub.2 H.sub.5
UV-1
H H CH.sub.3
C.sub.2 H.sub.5
None H CH.sub.3
C.sub.2 H.sub.5
UV-2
H H CH.sub.3
C.sub.2 H.sub.5
None H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-3
Cl Cl H C.sub.2 H.sub.5
None H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-4
F F H C.sub.2 H.sub.5
None H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-5
H Cl CH.sub.3
C.sub.2 H.sub.5
None H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-6
H Cl CH.sub.3
CF.sub.3
None H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-7
H Cl CH.sub.3
C.sub.2 F.sub.5
None H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-8
H Cl CH.sub.3
C.sub.2 H.sub.5
None H CH.sub.3
C.sub.2 H.sub.5
UV-9
Br Br H C.sub.2 H.sub.5
None H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-10
CH.sub.3 O
CH.sub.3 O
CH.sub.3
C.sub.2 H.sub.5
None H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-11
H CH.sub.3 O
CH.sub.3
C.sub.2 H.sub.5
None H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-12
H Cl CH.sub.3
C.sub.2 H.sub.5
None H CH.sub.3
n-C.sub.4 H.sub.9
UV-13
H H CH.sub.3
CH.sub.3
CH.sub.2
H CH.sub.3
C.sub.2 H.sub.5
UV-14
H H CH.sub.3
C.sub.2 H.sub.5
CH.sub.2
H CH.sub.3
C.sub.2 H.sub.5
UV-14
H H CH.sub.3
C.sub.2 H.sub.5
CH.sub.2
H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-15
Cl Cl H C.sub.2 H.sub.5
CH.sub.2
H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-16
F F H C.sub.2 H.sub.5
CH.sub.2
H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-17
H Cl CH.sub.3
C.sub.2 H.sub.5
CH.sub.2
H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-18
H Cl CH.sub.3
C.sub.2 H.sub.5
CH.sub.2
H CH.sub.3
C.sub.2 H.sub.5
UV-19
Br Br H C.sub.2 H.sub.5
CH.sub.2
H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-20
CH.sub.3 O
CH.sub.3 O
CH.sub.3
C.sub.2 H.sub.5
CH.sub.2
H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-21
H CH.sub.3 O
CH.sub.3
C.sub.2 H.sub.5
CH.sub.2
H C.sub.2 H.sub.5
n-C.sub.4 H.sub.9
UV-22
H Cl CH.sub.3
C.sub.2 H.sub.5
CH.sub.2
H CH.sub.3
n-C.sub.4 H.sub.9
UV-23
H H CH.sub.3
CH.sub.3
None CH.sub.3
C.sub.2 H.sub.5
n-C.sub.3 H.sub.7
UV-24
H H CH.sub.3
C.sub.2 H.sub.5
None CH.sub.3
C.sub.2 H.sub.5
n-C.sub.3 H.sub.7
UV-25
H H CH.sub.3
C.sub.2 H.sub.5
None CH.sub.3
C.sub.2 H.sub.5
n-C.sub.3 H.sub.7
UV-26
Cl Cl H C.sub.2 H.sub.5
None CH.sub.3
C.sub.2 H.sub.5
n-C.sub.3 H.sub.7
UV-27
F F H C.sub.2 H.sub.5
None CH.sub.3
C.sub.2 H.sub.5
n-C.sub.3 H.sub.7
UV-28
H Cl CH.sub.3
C.sub.2 H.sub.5
None CH.sub.3
C.sub.2 H.sub.5
n-C.sub.3 H.sub.7
UV-29
H Cl CH.sub.3
C.sub.2 H.sub.5
None CH.sub.3
C.sub.2 H.sub.5
n-C.sub.3 H.sub.7
UV-30
Br Br H C.sub.2 H.sub.5
None CH.sub.3
C.sub.2 H.sub.5
n-C.sub.3 H.sub.7
UV-31
CH.sub.3 O
CH.sub.3 O
CH.sub.3
C.sub.2 H.sub.5
None CH.sub.3
C.sub.2 H.sub.5
n-C.sub.3 H.sub.7
UV-32
H CH.sub.3 O
CH.sub.3
C.sub.2 H.sub.5
None CH.sub.3
C.sub.2 H.sub.5
n-C.sub.3 H.sub.7
UV-33
______________________________________
UV absorbing compounds of formula (I) can be prepared from the chromophore
of formula (III), below. The compounds of formula (III) can be readily
synthesized from inexpensively available starting materials such as
o-nitroaniline, 4-chloro-2-nitroaniline and m-aminoalkyl substituted
phenols by analogous procedures known in the art (See, for example, U.S.
Pat. No. 3,813,255 and FR 1,324,898). For example, the
2-(2'-hydroxy-4'-ethylaminophenyl)benzotriazole can be made by reacting
2-nitrobenzenediazonium chloride with 3-ethylaminophenol followed by
reductive ring closure of the azo dye to the desired benzotriazole.
Further compounds of formula (I) can be prepared in an analogous manner.
It will be understood in each example below, that one of the starting
reagents (for example, the alkylcarbonyl chloride) is the corresponding
enantiomeric mixture (preferably, a 40/60 to 60/40 enantiomeric mixture).
The comparative tert-amido compounds C.sub.2 -C.sub.5 were also made from
formula (III) following analogous procedure described in FR 1,324,898, the
entire disclosures of which are incorporated herein by reference.
##STR9##
Table 2 illustrates specific examples of the present invention prepared as
described above.
TABLE 2
__________________________________________________________________________
Solid
(m.p. .degree.C.)
Compound
Example
Compound or liquid
No.
__________________________________________________________________________
Comparison
##STR10## 169-170
C-2
Comparison
##STR11## 183-184
C-3
Comparison
##STR12## 147-148
C-4
Comparison
##STR13## 127-128
C-5
Comparison
##STR14## 108-109
C-6
Comparison
##STR15## 118-119
C-7
Comparison
##STR16## Liquid
C-8
Invention
##STR17## Liquid
I-1
Invention
##STR18## 80-82
I-2
__________________________________________________________________________
Photographic elements according to the present invention will typically
have at least one light sensitive silver halide emulsion layer and a
non-light sensitive layer, with the ultraviolet absorbing compound of
formula (I) being typically (but not necessarily) located in the non-light
sensitive layer. More preferably, a photographic element of the present
invention will have the non-light sensitive layer containing the
ultraviolet absorbing compound located above all light sensitive layers.
However, it is also contemplated that the ultraviolet absorbing compound
can additionally be present in another layer, such as an interlayer (or
even a light sensitive layer), particularly an interlayer located between
red and green sensitive layers in an element having blue, green and
red-sensitive layers coated in that order, on a support (particularly a
paper support). Any layer of the photographic element in which the UV
absorbing compounds of formula (I) are located will normally be a gel
layer, and the UV absorbing compound may particularly be dispersed therein
using a coupler solvent with or without additional auxilliary solvents
such as ethyl acetate.
The UV absorbing compounds can be directly dispersed in the element or
dispersed therein in droplets of a solvent dispersion. Alternatively, the
UV absorbing compounds of formula (I) can be loaded into a polymer latex
by themselves or with other compounds such as high boiling point organic
solvents or monomeric UV absorbing compounds. "Loading" a polymer latex is
generally described in U.S. Pat. No. 4,199,363 for example. Loading of a
polymer latex is also described, for example, in U.S. Pat. No. 4,203,716,
U.S. Pat. No. 4,214,047, U.S. Pat. No. 4,247,627, U.S. Pat. No. 4,497,929
and U.S. Pat. No. 4,608,424.
As described, UV absorbing compounds of the present invention are
preferably used by themselves in a photographic element. However, they may
be used in conjunction with other UV absorbing compounds if desired, such
as other benzotriazole based UV absorbers. Examples of such conventional
UV absorbing agents which can be used include:
2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole,
2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole,
2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-2H-benzotriazole,
2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chloro-2H-benzotriazole,
2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole,
2-(2-hydroxy-3,5-di(1,1-dimethylbenzyl)-phenyl)-2H-benzotriazole,
2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole, and those described in
U.S. Pat. No. 5,500,332 and commonly assigned allowed U.S. patent
application Ser. No. 08/346,717 filed Nov. 30, 1994 and commonly assigned
U.S. patent application Ser. No. 08/624,328 filed Mar. 29, 1996, the
disclosures of which are incorporated herein by reference. Other types of
UV absorbing agents such as p-hydroxybenzoates, phenylesters of benzoic
acid, salicylanilides and oxanilides, diketones, benzylidene malonate,
esters of .alpha.-cyano-cinnamic acid, and organic metal photostabilizers,
and others, as described in J. F. Rabek, Photostabilization of Polymers,
Principles and Applications, Elsevier Science Publishers LTD, England,
page 202-278(1990).
The UV absorbing compound is incorporated into the photographic element,
typically into a gelatin dispersion in an amount of between 0.2 g/m.sup.2
to 10 g/m.sup.2, and more preferably between 0.5 g/m.sup.2 to 5.0
g/m.sup.2. Furthermore, when incorporated as a solvent dispersion using a
water immiscible organic solvent, the weight ratio of high boiling, water
immiscible organic solvent to UV absorbing compound is preferably between
0.1 to 5.0 (that is, 0.1/1 to 5.0/1 of solvent/UV absorbing compound), and
more preferably between 0.2 to 3.0 (that is, 0.2/1 to 3.0/1 of solvent/UV
absorbing compound).
The UV absorbing compound of formula (I) is provided in any one or more of
the layers (for example, a hydrophilic colloid layer such as a gelatin
layer) of a photographic light-sensitive material (for example, a silver
halide photographic light-sensitive material), such as a surface
protective layer, an intermediate layer or a silver halide emulsion layer,
and the like. For example, in photographic paper the UV absorbing compound
of formula (I) with/without other UV absorbing compounds, may be
positioned above and/or below the red sensitive layer (typically adjacent
to it), the red sensitive layer typically being the uppermost light
sensitive layer in color paper, or even completely or partially within the
red sensitive layer. The UV absorbing compound is typically provided in a
given layer of a photographic element by coating the hydrophilic colloid
material (such as a gelatin emulsion) which contains the latex, onto a
support or another previously coated layer forming part of the element.
The photographic elements made by the method of the present invention can
be single color elements or multicolor elements. Multicolor elements
contain dye image-forming units sensitive to each of the three primary
regions of the spectrum. Each unit can be comprised of a single emulsion
layer or of multiple emulsion layers sensitive to a given region of the
spectrum. The layers of the element, including the layers of the
image-forming units, can be arranged in various orders as known in the
art. In an alternative format, the emulsions sensitive to each of the
three primary regions of the spectrum can be disposed as a single
segmented layer.
A typical multicolor photographic element comprises a support bearing a
cyan dye image-forming unit comprised of at least one red-sensitive silver
halide emulsion layer having associated therewith at least one cyan
dye-forming coupler, a magenta dye image-forming unit comprising at least
one green-sensitive silver halide emulsion layer having associated
therewith at least one magenta dye-forming coupler, and a yellow dye
image-forming unit comprising at least one blue-sensitive silver halide
emulsion layer having associated therewith at least one yellow dye-forming
coupler. The element can contain additional layers, such as filter layers,
interlayers, overcoat layers, subbing layers, and the like. All of these
can be coated on a support which can be transparent or reflective (for
example, a paper support).
Photographic elements of the present invention may also usefully include a
magnetic recording material as described in Research Disclosure, Item
34390, November 1992, or a transparent magnetic recording layer such as a
layer containing magnetic particles on the underside of a transparent
support as in U.S. Pat. No. 4,279,945 and U.S. Pat. No. 4,302,523. The
element typically will have a total thickness (excluding the support) of
from 5 to 30 microns. While the order of the color sensitive layers can be
varied, they will normally be red-sensitive, green-sensitive and
blue-sensitive, in that order on a transparent support, (that is, blue
sensitive furthest from the support) and the reverse order on a reflective
support being typical.
The present invention also contemplates the use of photographic elements of
the present invention in what are often referred to as single use cameras
(or "film with lens" units). These cameras are sold with film preloaded in
them and the entire camera is returned to a processor with the exposed
film remaining inside the camera. Such cameras may have glass or plastic
lenses through which the photographic element is exposed.
In the following discussion of suitable materials for use in elements of
this invention, reference will be made to Research Disclosure, September
1996, Number 389, Item 38957, which will be identified hereafter by the
term "Research Disclosure I." The Sections hereafter referred to are
Sections of the Research Disclosure I unless otherwise indicated. All
Research Disclosures referenced herein are published by Kenneth Mason
Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire
P010 7DQ, ENGLAND. The foregoing references and all other references cited
in this application, are incorporated herein by reference.
The silver halide emulsions employed in the elements of this invention can
be either negative-working, such as surface-sensitive emulsions or
unfogged internal latent image forming emulsions, or direct positive
emulsions of the unfogged, internal latent image forming type which are
positive working when development is conducted with uniform light exposure
or in the presence of a nucleating agent. Suitable emulsions and their
preparation as well as methods of chemical and spectral sensitization are
described in Sections I through V. Color materials and development
modifiers are described in Sections V through XX. Vehicles which can be
used in the elements of the present invention are described in Section II,
and various additives such as brighteners, antifoggants, stabilizers,
light absorbing and scattering materials, hardeners, coating aids,
plasticizers, lubricants and matting agents are described, for example, in
Sections VI through X and XI through XIV. Manufacturing methods are
described in all of the sections, other layers and supports in Sections XI
and XIV, processing methods and agents in Sections XIX and XX, and
exposure alternatives in Section XVI.
With negative working silver halide a negative image can be formed.
Optionally a positive (or reversal) image can be formed although a
negative image is typically first formed.
The photographic elements of the present invention may also use colored
couplers (e.g. to adjust levels of interlayer correction) and masking
couplers such as those described in EP 213 490; Japanese Published
Application 58-172,647; U.S. Pat. No. 2,983,608; German Application DE
2,706,117C; U.K. Patent 1,530,272; Japanese Application A-113935; U.S.
Pat. No. 4,070,191 and German Application DE 2,643,965. The masking
couplers may be shifted or blocked.
The photographic elements may also contain materials that accelerate or
otherwise modify the processing steps of bleaching or fixing to improve
the quality of the image. Bleach accelerators described in EP 193 389; EP
301 477; U.S. Pat. No. 4,163,669; U.S. Pat. No. 4,865,956; and U.S. Pat.
No. 4,923,784 are particularly useful. Also contemplated is the use of
nucleating agents, development accelerators or their precursors (UK Patent
2,097,140; U.K. Patent 2,131,188); electron transfer agents (U.S. Pat. No.
4,859,578; U.S. Pat. No. 4,912,025); antifogging and anti color-mixing
agents such as derivatives of hydroquinones, aminophenols, amines, gallic
acid; catechol; ascorbic acid; hydrazides; sulfonamidophenols; and non
color-forming couplers.
The elements may also contain filter dye layers comprising colloidal silver
sol or yellow and/or magenta filter dyes and/or antihalation dyes
(particularly in an undercoat beneath all light sensitive layers or in the
side of the support opposite that on which all light sensitive layers are
located) either as oil-in-water dispersions, latex dispersions or as solid
particle dispersions. Additionally, they may be used with "smearing"
couplers (e.g. as described in U.S. Pat. No. 4,366,237; EP 096 570; U.S.
Pat. No. 4,420,556; and U.S. Pat. No. 4,543,323.) Also, the couplers may
be blocked or coated in protected form as described, for example, in
Japanese Application 61/258,249 or U.S. Pat. No. 5,019,492.
The photographic elements may further contain other image-modifying
compounds such as "Developer Inhibitor-Releasing" compounds (DIR's).
Useful additional DIR's for elements of the present invention, are known
in the art and examples are described in U.S. Pat. Nos. 3,137,578;
3,148,022; 3,148,062; 3,227,554; 3,384,657; 3,379,529; 3,615,506;
3,617,291; 3,620,746; 3,701,783; 3,733,201; 4,049,455; 4,095,984;
4,126,459; 4,149,886; 4,150,228; 4,211,562; 4,248,962; 4,259,437;
4,362,878; 4,409,323; 4,477,563; 4,782,012; 4,962,018; 4,500,634;
4,579,816; 4,607,004; 4,618,571; 4,678,739; 4,746,600; 4,746,601;
4,791,049; 4,857,447; 4,865,959; 4,880,342; 4,886,736; 4,937,179;
4,946,767; 4,948,716; 4,952,485; 4,956,269; 4,959,299; 4,966,835;
4,985,336 as well as in patent publications GB 1,560,240; GB 2,007,662; GB
2,032,914; GB 2,099,167; DE 2,842,063, DE 2,937,127; DE 3,636,824; DE
3,644,416 as well as the following European Patent Publications: 272,573;
335,319; 336,411; 346, 899; 362, 870; 365,252; 365,346; 373,382; 376,212;
377,463; 378,236; 384,670; 396,486; 401,612;. 401,613.
DIR compounds are also disclosed in "Developer-Inhibitor-Releasing (DIR)
Couplers for Color Photography," C. R. Barr, J. R. Thirtle and P. W.
Vittum in Photographic Science and Engineering, Vol. 13, p. 174 (1969),
incorporated herein by reference.
It is also contemplated that the concepts of the present invention may be
employed to obtain reflection color prints as described in Research
Disclosure, November 1979, Item 18716, available from Kenneth Mason
Publications, Ltd, Dudley Annex, 12a North Street, Emsworth, Hampshire
P0101 7DQ, England, incorporated herein by reference. This reference and
all other references cited in this application are incorporated herein by
reference. The emulsions and materials to form elements of the present
invention, may be coated on pH adjusted support as described in U.S. Pat.
No. 4,917,994; with epoxy solvents (EP 0 164 961); with additional
stabilizers (as described, for example, in U.S. Pat. No. 4,346,165; U.S.
Pat. No. 4,540,653 and U.S. Pat. No. 4,906,559); with ballasted chelating
agents such as those in U.S. Pat. No. 4,994,359 to reduce sensitivity to
polyvalent cations such as calcium; and with stain reducing compounds such
as described in U.S. Pat. No. 5,068,171 and U.S. Pat. No. 5,096,805. Other
compounds useful in the elements of the invention are disclosed in
Japanese Published Applications 83-09,959; 83-62,586; 90-072,629,
90-072,630; 90-072,632; 90-072,633; 90-072,634; 90-077,822; 90-078,229;
90-078,230; 90-079,336; 90-079,338; 90-079,690; 90-079,691; 90-080,487;
90-080,489; 90-080,490; 90-080,491; 90-080,492; 90-080,494; 90-085,928;
90-086,669; 90-086,670; 90-087,361; 90-087,362; 90-087,363; 90-087,364;
90-088,096; 90-088,097; 90-093,662; 90-093,663; 90-093,664; 90-093,665;
90-093,666; 90-093,668; 90-094,055; 90-094,056; 90-101,937; 90-103,409;
90-151,577.
The silver halide used in the photographic elements may be silver
iodobromide, silver bromide, silver chloride, silver chlorobromide, silver
chloroiodobromide, and the like. For example, the silver halide used in
the photographic elements of the present invention may contain at least
90% silver chloride or more (for example, at least 95%, 98%, 99% or 100%
silver chloride). In the case of such high chloride silver halide
emulsions, some silver bromide may be present but typically substantially
no silver iodide. Substantially no silver iodide means the iodide
concentration would be no more than 1%, and preferably less than 0.5 or
0.1%. In particular, in such a case the possibility is also contemplated
that the silver chloride could be treated with a bromide source to
increase its sensitivity, although the bulk concentration of bromide in
the resulting emulsion will typically be no more than about 2 to 2.5% and
preferably between about 0.6 to 1.2% (the remainder being silver
chloride). The foregoing % figures are mole %.
The type of silver halide grains preferably include polymorphic, cubic, and
octahedral. The grain size of the silver halide may have any distribution
known to be useful in photographic compositions, and may be ether
polydipersed or monodispersed.
Tabular grain silver halide emulsions may also be used. Tabular grains are
those with two parallel major faces each clearly larger than any remaining
grain face and tabular grain emulsions are those in which the tabular
grains account for at least 30 percent, more typically at least 50
percent, preferably>70 percent and optimally>90 percent of the total grain
projected area. The tabular grains can account for substantially all (>97
percent) of the total grain projected area. The tabular grain emulsions
can be high aspect ratio tabular grain emulsions - - - i.e., ECD/t>8,
where ECD is the diameter of a circle having an area equal to the grain
projected area and t is the tabular grain thickness; intermediate aspect
ratio tabular grain emulsions - - - i.e., ECD/t=5 to 8; or low aspect
ratio tabular grain emulsions - - - i.e., ECD/t=2 to 5. The emulsions
typically exhibit high tabularity (T), where T (i.e., ECD/t.sup.2)>25 and
ECD and t are both measured in micrometers (.mu.m). The tabular grains can
be of any thickness compatible with achieving an aim average aspect ratio
and/or average tabularity of the tabular grain emulsion. Preferably the
tabular grains satisfying projected area requirements are those having
thicknesses of<0.3 .mu.m, thin (<0.2 .mu.m) tabular grains being
specifically preferred and ultrathin (<0.07 .mu.m) tabular grains being
contemplated for maximum tabular grain performance enhancements. When the
native blue absorption of iodohalide tabular grains is relied upon for
blue speed, thicker tabular grains, typically up to 0.5 .mu.m in
thickness, are contemplated.
High iodide tabular grain emulsions are illustrated by House U.S. Pat. No.
4,490,458, Maskasky U.S. Pat. No. 4,459,353 and Yagi et al EPO 0 410 410.
Tabular grains formed of silver halide(s) that form a face centered cubic
(rock salt type) crystal lattice structure can have either {100} or {111}
major faces. Emulsions containing {111} major face tabular grains,
including those with controlled grain dispersities, halide distributions,
twin plane spacing, edge structures and grain dislocations as well as
adsorbed {111} grain face stabilizers, are illustrated in those references
cited in Research Disclosure I, Section I.B.(3) (page 503).
The silver halide grains to be used in the invention may be prepared
according to methods known in the art, such as those described in Research
Disclosure I and James, The Theory of the Photographic Process. These
include methods such as ammoniacal emulsion making, neutral or acidic
emulsion making, and others known in the art. These methods generally
involve mixing a water soluble silver salt with a water soluble halide
salt in the presence of a protective colloid, and controlling the
temperature, pAg, pH values, etc, at suitable values during formation of
the silver halide by precipitation.
The silver halide to be used in the invention may be advantageously
subjected to chemical sensitization with noble metal (for example, gold)
sensitizers, middle chalcogen (for example, sulfur) sensitizers, reduction
sensitizers and others known in the art. Compounds and techniques useful
for chemical sensitization of silver halide are known in the art and
described in Research Disclosure I and the references cited therein.
The photographic elements of the present invention, as is typical, provide
the silver halide in the form of an emulsion. Photographic emulsions
generally include a vehicle for coating the emulsion as a layer of a
photographic element. Useful vehicles include both naturally occurring
substances such as proteins, protein derivatives, cellulose derivatives
(e.g., cellulose esters), gelatin (e.g., alkali-treated gelatin such as
cattle bone or hide gelatin, or acid treated gelatin such as pigskin
gelatin), gelatin derivatives (e.g., acetylated gelatin, phthalated
gelatin, and the like), and others as described in Research Disclosure I.
Also useful as vehicles or vehicle extenders are hydrophilic
water-permeable colloids. These include synthetic polymeric peptizers,
carriers, and/or binders such as poly(vinyl alcohol), poly(vinyl lactams),
acrylamide polymers, polyvinyl acetals, polymers of alkyl and sulfoalkyl
acrylates and methacrylates, hydrolyzed polyvinyl acetates, polyamides,
polyvinyl pyridine, methacrylamide copolymers, and the like, as described
in Research Disclosure I. The vehicle can be present in the emulsion in
any amount useful in photographic emulsions. The emulsion can also include
any of the addenda known to be useful in photographic emulsions. These
include chemical sensitizers, such as active gelatin, sulfur, selenium,
tellurium, gold, platinum, palladium, iridium, osmium, rhenium, rhodium,
ruthenium, phosphorous, or combinations thereof. Chemical sensitization is
generally carried out at pAg levels of from 5 to 10, pH levels of from 5
to 8, and temperatures of from 30.degree. to 80.degree. C., as illustrated
in Research Disclosure I, Section IV (pages 510-511) and the references
cited therein.
The silver halide may be sensitized by sensitizing dyes by any method known
in the art, such as described in Research Disclosure I. The dye may be
added to an emulsion of the silver halide grains and a hydrophilic colloid
at any time prior to (e.g., during or after chemical sensitization) or
simultaneous with the coating of the emulsion on a photographic element.
The dyes may, for example, be added as a solution in water or in an
alcohol. The dye/silver halide emulsion may be mixed with a dispersion of
color image-forming coupler immediately before coating or in advance of
coating (for example, 2 hours).
Photographic elements of the present invention are preferably imagewise
exposed using any of the known techniques, including those described in
Research Disclosure I, section XVI. This typically involves exposure to
light in the visible region of the spectrum, and typically such exposure
is of a live image through a lens, although exposure can also be exposure
to a stored image (such as a computer stored image) by means of light
emitting devices (such as light emitting diodes, CRT and the like).
Photographic elements comprising the composition of the invention can be
processed in any of a number of well-known photographic processes
utilizing any of a number of well-known processing compositions,
described, for example, in Research Disclosure I, or in T. H. James,
editor, The Theory of the Photographic Process, 4th Edition, Macmillan,
New York, 1977. In the case of processing a reversal color element, the
element is first treated with a black and white developer followed by
treatment with a color developer to produce a positive dye image. The
negative color element, the first developer is a color developer so as to
produce a negative dye image. Preferred color developing agents are
p-phenylenediamines. Especially preferred are:
4-amino N,N-diethylaniline hydrochloride,
4-amino-3-methyl-N,N-diethylaniline hydrochloride,
4-amino-3-methyl-N-ethyl-N-(.beta.-(methanesulfonamido) ethylaniline
sesquisulfate hydrate,
4-amino-3-methyl-N-ethyl-N-(.beta.-hydroxyethyl)aniline sulfate,
4-amino-3-.beta.-(methanesulfonamido)ethyl-N,N-diethylaniline hydrochloride
and
4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine di-p-toluene sulfonic acid.
Development is followed by bleach-fixing, to remove silver or silver
halide, washing and drying.
The present invention will be further described in the examples below which
illustrate UV absorbing compounds and photographic elements of this
invention.
EXAMPLES
For making compounds described in Table 2,
2-(2'-hydroxy-4'-aminoethylphenyl)benzotriazole derivatives were required.
These were synthesized by reduction of the corresponding
acetamido-substituted compound with alane in about 90% yield by similar
procedure known in the art (see, for example, Lal C. Vishwakarma et al,
Heterocycles, 19, 1453 (1982)).
Properties of the UV Absorbers of the Present Invention
Physical properties, including optical absorption profiles were measured
for various of the compounds of the present invention, as well as
comparative compounds, as shown in Table 3 below. In Table 3,
.sup..lambda. max is the wavelength of maximum absorption (measured in
MeOH as indicated in the Table), .epsilon..sub.max is the extinction
coefficient, and the half bandwidth is the width of the absorption peak
centered about .lambda..sub.max as measured at one-half the maximum
absorption .lambda..sub.max. All of the foregoing were measured in
methanol. The percent yields of the products are not optimized.
TABLE 3
______________________________________
Half
Band
.lambda..sub.max (nm)
.epsilon..sub.max
width
Example No.
% Yield (in MeOH) (.times.10.sup.4)
(nm) Remark
______________________________________
C-1 (II-A/II-B)
-- 342 1.57 86 Solid
C-2 64 338 2.24 68 Solid
C-3 58 344 2.24 68 Solid
C-4 94 336 1.90 68 Solid
C-5 90 342 2.02 68 Solid
C-6 87 337 1.96 68 Solid
C-7 90 336 1.90 68 Solid
C-8 98 342 2.00 68 Liquid
I-1 86 342 2.00 68 Liquid
I-2 88 337 1.99 68 Solid
______________________________________
The comparative examples C-1 through C-8 in Table 3 are lacking asymmetric
carbon center.
Table 1 illustrates the higher melting character of the comparative
examples related to prior art. As a result, they are prone to crystallize
out in the dispersion and/or coating even if they have racemic chains
particularly in primary carboxamido substituted compounds. As shown below,
in Table 4 the comparative examples, if solid, are prone to crystallize
out in the dispersion and/or coating. If these happen to be liquid, their
intrinsic light stability is quite inferior.
Photographic Evaluation
1.45 g of UV absorber was dissolved at elevated temperature
(50.degree.-70.degree. C.) in 480 mg of 1,4-cyclohexylenedimethylene
bis-(2-ethylhexanoate) and, if UV absorber was a solid at room
temperature, an additional 4.35 g of ethyl acetate was used. This oil
phase was added with high shear stirring to a 70.degree. C. aqueous
gelatin solution (containing per liter 40.1 g of gelatin and 31.0 mL of
10% aqueous Alkanol - XC) and passed five times through a colloid mill for
adequate particle size reduction. The dispersion is inspected
microscopically for general particle size and crystallinity, and coated
about 0.108.times.10.sup.-4 moles/m.sup.2 on an acetate base in a two
layer SOC-type format, allowed to dry and the coating is also inspected
microscopically for crystallinity (See Table 4). Fresh coated spectral
absorption data are recorded using a Perkin-Elmer Lambda 4C High
Performance UV-VIS Spectrophotometer, and coated samples are HID (50 Klux
Daylight; 315-700 nm) and HIS (50 Klux Sunshine; 280-700 nm) tested and
compared to fresh data in order to obtain UV absorber intrinsic light
stability information. (For HID and HIS explanation, see Lewis R. Koller,
Ultraviolet Radiation, John Wiley & Sons, Inc., N.Y., N.Y., 1965).
Absorption spectra for various of the compounds were obtained in methanolic
solution (Table 3). Absorption spectra from fresh coatings were obtained
as described below and shown in FIG. 1. In particular, FIG. 1 shows the
absorption spectra in coating for inventive compound I-1 and the control
compounds C-1 (II-A/II-B) in total transmission (TT) mode of the
spectrophotometer. Note from FIG. 1 that inventive UV absorbing compound
I-1 (shown by dashed line) exhibits, in addition to a steeper slope at its
longer wavelengths of absorption (that is, near 380 nm) and a particular
drop-off to a lower absorption at their longest wavelength of the
absorption, a higher extinction coefficient than comparative control
compounds C-1(II-A/II-B)(solid line) as measured from fresh coating of
their respective dispersions.
Microscopic observations for crystallinity in experimental UV absorber
dispersions and coatings of these materials and their absorption spectra
were performed as described here. Microscopy is undertaken in the
preparation of dispersions of experimental materials in order to provide
an initial indication of physical properties such as general particle size
and stability (that is, tendency to crystallize). The microscopic particle
size characterizations are performed using oil immersion optics -1000x
microscopy, and -200x cross-polarized microscopy is used for crystal
characterization. Microscopic evaluation of the coatings is also
undertaken because an acceptable non-crystalline dispersion may
recrystallize in the coated format. Assuming there are no
recrystallization problems, duplicate samples are spectrophotometrically
measured using a Perkin-Elmer High Performance Lambda 4C spectrometer.
These samples are then submitted for two Week HID and HIS light stability
testing, and the post-testing spectra is measured and compared to the
fresh measurements in order to determine intrinsic light stability of the
UV absorber. Since the experimental dispersion formulation used for these
experiments is common and only optimized from the standpoint of low
melting solids and its beneficial effect on dispersion crystallinity,
coated spectroscopy data are obtained primarily using the total
transmission mode of operation where an integrating sphere is used in the
spectrophotometer. This has the effect of diminishing light scattering
effects due to particle size, so misleading extinction differences caused
by light scattering in the specular mode can be overlooked.
A microscopic check for crystal formation from the above procedure, yielded
the results in Table 4 below:
TABLE 4
______________________________________
Tendency to Form Undesirable Crystals
Compound No.
Example No.
Dispersion Coating
______________________________________
I-1 Invention A liquid A liquid
I-2 Invention It did not crystallize
It did not crystallize
C-1 (II-AAI-B)
Comparison
-- --
C-2 Comparison
Crystallized Crystallized
C-3 Comparison
Crystallized Crystallized
C-4 Comparison
Crystallized Crystallized
C-5 Comparison
Crystallized Crystallized
C-6 Comparison
Crystallized Crystallized
C-7 Comparison
Crystallized Crystallized
C-8 Comparison
A liquid A liquid
______________________________________
Table 4 illustrates how UV absorbing compound I-2 of the present invention
did not form any detectable crystals either in dispersion or in coating.
On the other hand, the comparison compounds C-6 and C-7 being an exact
match of invention compound I-2 in terms of number of atoms and position
of amido group attachment in the hydroxyphenyl ring, but lacking a racemic
carbon center crystallized out in the coatings. This observation clearly
illustrates the superiority of asymmetric carbon containing UV absorbing
solid compounds of formula (I). Incidentally, whenever some UV absorbing
compounds, such as example C-8, become liquids their intrinsic light
stability often is inferior as will be illustrated in Table 5.
Intrinsic light stability data for UV absorbing compounds of this invention
are summarized in Table 5. A combination of the compounds II-A & II-B has
been used as a Control in each coating set and is referred to as C-1. The
optical density loss, relative to the control coatings, was measured at
350 nm from coating spectral data.
TABLE 5
______________________________________
Light Stability
Sample No.
2 Week HID
4 Week HID
2 Week HIS
4 Week HIS
______________________________________
C-1 (II-A/II-B)
-8.63 -11.47 -8.70 -16.18
C-7 -7.44 -13.77 -8.08 -24.91
C-8 -4.35 -14.26 -5.87 -27.69
I-1 -2.08 -6.53 -1.51 -14.10
I-2 -5.37 -10.73 -4.28 -19.56
______________________________________
The intrinsic light stability data from Table 5 clearly illustrate that the
inventive compound I-1 is better than the control compounds II-A/II-B
(C-1) and particularly better than its exact match C-8 while C-8 and I-1
both being liquid compounds. Also, the invention compound I-2 containing
an asymmetric carbon atom is far superior to its non-racemic exact match
version C-7 in terms of light stability and no crystal forming tendency as
shown in Table 4. Most preferred UV absorbing compounds of this invention
are I-1 and I-1 based, nonetheless I-2 and I-2 based compounds are
photographically important as well. The data from Table 5 suggest that the
presence of asymmetric carbon center seems to enhance intrinsic light
stability of the UV absorbing compounds of this invention.
The present invention also specifically contemplates multilayer
photographic elements as described in Research Disclosure, February 1995,
Item 37038 (pages 79-115). Particularly contemplated is the use of any of
the enantiomeric mixtures of formula (I) (particularly a 50/50 mixture of
the two enantiomers) in such elements. Particularly, a 50/50 enantiomeric
mixture of any one of the compounds of this invention may be used as the
UV absorbing compound in an overcoat of each of the photographic elements
described in detail in Sections XVII through XXII of that Research
Disclosure.
The preceding examples are set forth to illustrate specific embodiments of
this invention and are not intended to limit the scope of the compositions
or materials of the invention. It will be understood that variations and
modifications can be effected within the spirit and scope of the
invention.
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